Discount retailer Dollar General Corp. said its sales over the Thanksgiving weekend and the start of the holiday shopping season were encouraging, but it remains cautious about the rest of the year, noting that consumer spending remains tight. Third-quarter net income was $208 million, or 62 cents per share, compared to $171 million, or 50 cents, a year earlier. Same-store sales rose 4 percent. The Tennessee company is forecasting full-year adjusted earnings of up to $2.85 per share.